Posted
by
samzenpus
on Thursday January 19, 2012 @04:42PM
from the luck-of-the-draw dept.

ananyo writes "A Scottish intelligence study that began 80 years ago has borne new fruit. Researchers have tracked down the study's surviving participants — who joined the study when they were 11 years old — to estimate the role that our genes have in maintaining intelligence through to old age. After conducting fresh intelligence tests on the surviving participants, the researchers tested the DNA samples they had collected for the presence of more than half a million common genetic variants, each affecting only a single letter in the DNA sequence of the genome. The team then calculated whether these variants were associated with cognitive stability — how well intelligence had been maintained over time. The sample size of 2,000 people was too small to grant the statistical power needed to track down individual genetic signatures associated with cognitive stability. But it was enough to estimate how much genetics contributes to cognitive aging. The team found that these variants accounted for nearly one-quarter of the differences in cognitive stability."

Maybe. Or maybe the genetic factors killed off the faster-declining people prior to old age. Based on the summary, I would say that "Among people who survived to old age, genetic factors account for approximately 25% of mental decline."

My theory was that the other 3/4 was associate with not wasting time and grey matter watching inane, worthless, stupid reality shows on TV 24/7....and actually doing something with their minds into their old age.

Of course..diet and exercise certainly had to have a lot to do with it too, I'd guess...

My grandmother must have been an anomaly, then. Once she left the farm at age 55 about the only exercise she got was doing housework. I never saw her doing any mental puzzles, and she watched a lot of TV. The only time I ever saw any mental decline in her was in her seventies, and it turned out to be due to the prescription drugs her doctor was feeding her.

Diet? She was born in 1903, had eggs and bacon and buttered toast for breakfast, cooked with lard most of her life, etc. Her doctor said if she didn't ge

Useful for confirmation, but not new or unexpected. The/. history has articles about taxi driver training leading to neural restructuring in favor of mapping and geographical awareness. There are some mentally destructive conditions that we don't know how to prevent yet, but in general, you get good at what you do a lot. If you spend your time hauling heavy boxes, you will get stronger (until you hit a physical limit). If you spend your time solving puzzles, studying new scientific research, and practicing your 24 dimensional calculus, you will get better at those. If you spend all your time watching gossip shows on TV and sitting on the couch, you very well may become one with the couch, mentally and physically.

The study only sampled a subset of the genome (certain SNPs), there could be other variations in the genome that contribute even more. We simply can't tell from the study. All we can say is that this study suggests at least a quarter of the variation is explained by the subset of the genotype they have sampled.

One of the nice things they teach you when you learn about how human SNP linkage analyses (for those of you following along at home: a different test performed on the same data, when it's available for a whole family) are done is that the SNPs are often linked with a whole-gene allele. It's true that there might be more out there, but it's not going to be some surprisingly huge number like 50%. A significant portion of SNPs can be inferred from each other with extremely high reliability, suggesting they're

Not necessarily. If I'm reading this right, all this study showed that there was a correlation between certain DNA sequences and cognitive stability in 25% of the people in the study. That's it. "Mental exercise, diet, etc," could account for the other 75%, sure, but it could also be that the other 75% is purely genetic, but the researchers were looking at the wrong thing. Or that the correlation is pure coincidence. Or that there was a freak storm of cosmic rays that changed the DNA of 25% of the study participants[1]. Or that their methodology was flawed. Or that their methodology was correct but the sample size was just too small. Et cetera, ad infinitum.

In short, the study—any study—says what it says. What it doesn't say, it doesn't imply.

If there are N genes required for intelligence out of a set of M, unless N==M you cannot identify all of N by looking at what is common to everyone. That's a common but problematic flaw in genetic studies. It's also why markers that indicate a propensity for disease can't tell you if you will get that disease. If the studies so far don't map which sets of genetic markers are significant (and what epigenetic states are required to make them significant), this positive indication approach has limited value -

I make fun, but with all honesty I think I'm a really good example of the traits looked for in this study. I was raised by adopted parents, a restaurant manager and a hair stylist. My natural parents are both computer programmers. I knew neither of them growing up, and yet I was writing software while I was still in elementary school. I know it isn't their exact study, but something regarding intelligence is definitely passed down very strongly.

The underlying problem of Nazi Science was that it tried to set an objective standard for what is a good quality and what is a bad quality, just as you appear to be implying that there is a measure of smartness such that it is always desirable to increase your score on that measure.

We're already far too far down the path where test-taking and homogeneity have substituted for imagination and determination. It is t

Indeed. My paternal grandmother, born in 1903 and who cooked with lard and was told by five doctors, one after the other (who all died) said she'd die soon from her high cholesterol, lived a hundred years. Her brother started amoking at age 12 and quit at age 82, ten years before he died. Her other siblings are likewise long lived (Grandpa died in an accident at age 60, fell four stories carrying two 100 lb sacks of feed... Purina was guilty of negligent manslaughter). My other grandparents lived until thei

The art of distillation began with the Babylonians in Mesopotamia (in what is now Iraq) from at least the 2nd millennium BC,[3] with perfumes and aromatics being distilled long before potable spirits. Distillation was brought from Africa to Europe by the Moors,[4][5] and its use spread through the monasteries,[6] largely for medicinal purposes, such as the treatment of colic, palsy, and smallpox.[7]

The Scottish don't think of themselves as being stupid (that's the stereotype of the Irish, which I'm not saying is true at all). Scots joke: "A Scotsman moves to England. The average IQ of both countries increases""

The GP is mocking people who dispute books like The Bell Curve [amazon.com], a book which is frequently cited by scientific racists as evidence than dark skinned people are less intelligent than light skinned people.

Bingo. I also realize that was a joke, but I've argued with people who think that intelligence is not heritable, but support evolution. I point out that man's ancestors were less intelligent, so clearly in order for man to become more intelligent over time, intelligence must be heritable to some degree.

A guy named Dr. Thomas Bouchard [wikipedia.org] did something similar studying fraternal vs. identical twins, and found a genetic contribution of about 75% (for intelligence, not age-related decline in intelligence).

His work is considered one of the landmark studies on the heritability of intelligence. And yes, various groups attempted to suppress his research and get him fired.

Who said having a higher intelligence was a good thing? Don't most of the business majors make more than engineers. If we go by that standard, intelligence is probably a liability. With intelligence and understanding come options and having more options isn't necessary the best thing in the world.

I know you're being sarcastic, but I know many very intelligent people of all races, and many really stupid people of all races, and the intilligent members of all the races surely have a genetic component to their giftedness.

There are other reasons for stupidity than genetics; fetal alcohol syndrome, or simple things like the baby's umbilical cord being wrapped around its neck, head trauma in the infant, etc. But high intelligence surely has a genetic component, no matter what the genuis' race. It is in no

Comparing variation between and across races has no bearing on whether one race is, on average, smarter than another. Try reading The Bell Curve. It's unfortunate, disheartening, politically incorrect, etc but true that some races are smarter than others, on average.

What is race? Are you attempting to link intelligence to skin color? Head shape? Fast-twitch muscle fibers in the legs?

Scientists don't know what race is for this purpose because simply going "hyuck, we all know black people have dark skin and big ol lips hyuck hyuck" isn't anything to base research on due to a huge number of genetic differences - as different within dark-skinned peoples as between dark- and light-skinned peoples. In short, there is no "black" or "white" for any purpose except socia

I said it before and I will say it again: you cannot give a number like x% of your intelligence is determined by genes unless you define the variation of your genes (difficult, but doable in theory) and the variation of your environment (nearly impossible) first. That is because logically, in very similar environments (such as some egalitarian countries) genes will dominate, and in a homogeneous gene pool the environment will dominate.